// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CONTENT_RENDERER_MEDIA_MEDIA_STREAM_VIDEO_TRACK_H_
#define CONTENT_RENDERER_MEDIA_MEDIA_STREAM_VIDEO_TRACK_H_

#include <vector>

#include "base/compiler_specific.h"
#include "base/gtest_prod_util.h"
#include "base/macros.h"
#include "base/threading/thread_checker.h"
#include "content/common/content_export.h"
#include "content/public/renderer/media_stream_video_sink.h"
#include "content/renderer/media/media_stream_track.h"
#include "content/renderer/media/media_stream_video_source.h"
#include "content/renderer/media/secure_display_link_tracker.h"

namespace content {

// MediaStreamVideoTrack is a video specific representation of a
// blink::WebMediaStreamTrack in content. It is owned by the blink object
// and can be retrieved from a blink object using
// WebMediaStreamTrack::getExtraData() or MediaStreamVideoTrack::GetVideoTrack.
class CONTENT_EXPORT MediaStreamVideoTrack : public MediaStreamTrack {
public:
    // Help method to create a blink::WebMediaStreamTrack and a
    // MediaStreamVideoTrack instance. The MediaStreamVideoTrack object is owned
    // by the blink object in its WebMediaStreamTrack::ExtraData member.
    // |callback| is triggered if the track is added to the source
    // successfully and will receive video frames that match |constraints|
    // or if the source fail to provide video frames.
    // If |enabled| is true, sinks added to the track will
    // receive video frames when the source deliver frames to the track.
    static blink::WebMediaStreamTrack CreateVideoTrack(
        MediaStreamVideoSource* source,
        const blink::WebMediaConstraints& constraints,
        const MediaStreamVideoSource::ConstraintsCallback& callback,
        bool enabled);

    static MediaStreamVideoTrack* GetVideoTrack(
        const blink::WebMediaStreamTrack& track);

    // Constructor for video tracks.
    MediaStreamVideoTrack(
        MediaStreamVideoSource* source,
        const blink::WebMediaConstraints& constraints,
        const MediaStreamVideoSource::ConstraintsCallback& callback,
        bool enabled);
    ~MediaStreamVideoTrack() override;

    // MediaStreamTrack overrides.
    void SetEnabled(bool enabled) override;
    void SetContentHint(
        blink::WebMediaStreamTrack::ContentHintType content_hint) override;
    void Stop() override;
    void getSettings(blink::WebMediaStreamTrack::Settings& settings) override;

    void OnReadyStateChanged(blink::WebMediaStreamSource::ReadyState state);

    const blink::WebMediaConstraints& constraints() const { return constraints_; }

private:
    // MediaStreamVideoSink is a friend to allow it to call AddSink() and
    // RemoveSink().
    friend class MediaStreamVideoSink;
    FRIEND_TEST_ALL_PREFIXES(MediaStreamRemoteVideoSourceTest, StartTrack);
    FRIEND_TEST_ALL_PREFIXES(MediaStreamRemoteVideoSourceTest, RemoteTrackStop);
    FRIEND_TEST_ALL_PREFIXES(PepperToVideoTrackAdapterTest, PutFrame);

    // Add |sink| to receive state changes on the main render thread and video
    // frames in the |callback| method on the IO-thread.
    // |callback| will be reset on the render thread.
    // These two methods are private such that no subclass can intercept and
    // store the callback. This is important to ensure that we can release
    // the callback on render thread without reference to it on the IO-thread.
    void AddSink(MediaStreamVideoSink* sink,
        const VideoCaptureDeliverFrameCB& callback,
        bool is_sink_secure);
    void RemoveSink(MediaStreamVideoSink* sink);

    std::vector<MediaStreamVideoSink*> sinks_;

    // |FrameDeliverer| is an internal helper object used for delivering video
    // frames on the IO-thread using callbacks to all registered tracks.
    class FrameDeliverer;
    const scoped_refptr<FrameDeliverer> frame_deliverer_;

    const blink::WebMediaConstraints constraints_;

    // Weak ref to the source this tracks is connected to.
    base::WeakPtr<MediaStreamVideoSource> source_;

    // This is used for tracking if all connected video sinks are secure.
    SecureDisplayLinkTracker<MediaStreamVideoSink> secure_tracker_;

    DISALLOW_COPY_AND_ASSIGN(MediaStreamVideoTrack);
};

} // namespace content

#endif // CONTENT_RENDERER_MEDIA_MEDIA_STREAM_VIDEO_TRACK_H_
